The daily protein requirement for an adult depends on several factors, such as age, gender, weight, and physical activity. Generally, it is recommended to consume about 1.2 grams of protein per kilogram of body weight per day. For example, a person weighing 70 kilograms should consume about 84 grams of protein per day. However, the protein requirement may be higher for physically active individuals or the elderly, where the recommendation can rise to up to 1.4 grams per kilogram.